Adherent cell culture systems require a surface on which to culture cells, such as a culture container or microcarrier (such as gelatin, porous glass, collagen or cellulose). The surface may also be coated with an extracellular matrix to increase adhesion properties. Feeder cells may also be used to coat the surface to provide a more adherent surface as well as nutrients to culturing cells. When the cultured cells are ready to harvest, usually an enzyme is used to separate the cultured cells from the surface. However, use of enzymes or other chemicals to separate cultured cells from the surface can cause damage to the cultured cells.